DESCRIPTION (Applicant's Description): The specific aim of this training grant renewal proposal is to continue the development of research scientists that are well versed in physics, mathematics, engineering and computer science, who also understand the application of these disciplines to the instruments and techniques used in the practice of radiology, nuclear medicine and radiation oncology. The focus of the training is the UCLA Biomedical Physics Interdepartmental Graduate Program. Biomedical Physics includes the areas of study usually considered to be Medical Physics, but is broader in scope. Thesis topics include mathematical modeling of physiological processes, systems for production of radiopharmaceuticals, cryo- electron microscopy and development of database and picture archiving systems in radiology, as well as the expected studies in diagnostic radiology, radiation therapy and medical imaging. In the last 25 years the fields of radiology, nuclear medicine and radiation oncology have undergone a technological explosion. 25 years ago, imaging with NMR or ultrasound, or the concept of a filmless radiology department had been inconceivable. In the current environment the medical physicist cannot be a person who is simply trained in the performance of certain well established testing procedures with a limited understanding of the underlying principles. Medical physicists must be educated to the level of clearly understanding the hardware and applications in terms of the physics of the medical devices. They must have the understanding and knowledge to evaluate totally new devices and applications, and be able to add their own input to overcome inadequacies of a device or procedure. They should have the capacity to develop new instruments based on their own educational background and the understanding developed through experience in dealing with clinical problems. The UCLA Biomedical physics Interdepartmental Graduate Program has had an exemplary record in training individuals for these roles at the predoctoral and postdoctoral level. It has the programmatic infrastructure in place for the program, it has a rich and varied environment, but most important, it has a dedicated and outstanding faculty.